At other major Universities, changing colleges is about as easy as changing majors. They’re not all like UCD. At most universities, you’re accepted into the school itself as a whole. Generally, being accepted into a college, or changing a college, is just as easy as changing a major.
Sometimes, however, whether you’re accepted into a major (or a college) has to do with the level of demand for that major (or college). Even with high demand majors, all a student is really doing for the first two years is clearing core courses off their plate so it hardly matters what the major is declared as just so long as prerequisites are being taken. Being accepted into an individual college sometimes isn’t even possible until the junior year. For example, at the University of Georgia it is nearly impossible to get into Grady, the journalism school. You have to apply once you have completed a certain number of hours, you can’t just walk in and declare what journalism major you want (you can be pre-journalism until then). But it isn’t even an issue getting into the College of Ag, the College of Arts and Sciences, or most others on campus because they’re not restricted. At other schools there are other things that are hard to get into. Nursing, for instance, at many schools is difficult to get into. But most majors, and colleges, at most schools are not.
Most students start out in a college they think they want to be in or the general Arts and Sciences college. There are very few people who don’t consider (or actually change) their majors throughout college. Its not hard at all to do, even if you’re changing colleges unless you pick a high demand program.